PhD opportunity (self-funded) at the University of St. Andrews, UK: Why do gulls and pigeons nest on particular buildings? Why are seals restricted to a particular section of coast? Why do people live in particular neighbourhoods? Non-lethal effects, such as avoidance of predators or disturbance, have been shown to have dominant effects on prey behaviour, survival, population dynamics, community structure and trophic interactions. Consequently an animal’s perception of risk may fundamentally determine its distribution, frequently overriding habitat quality. Predicting changes in distribution in response to human disturbance and climate change therefore requires an integration of how animals perceive predation and disturbance risk and how predation and disturbance risk might change, as well as the current approach of simply looking at how climate may affect habitat quality. Despite this need to integrate both habitat quality and risk (the starvation-predation risk trade-off) into understanding the density and distribution of animals, how animals perceive risk as a consequence of local experience of potential predators and the disturbance they cause is almost unstudied. This proposed PhD research aims to determine how the distribution of a model animal species results from experimentally manipulated experience of predation risk and disturbance.
The study system involves redshanks – a common shorebird – that have been individually colour-ringed near St Andrews since 2006. Each year juvenile birds enter the wintering population for the first time and then establish a wintering range that is then maintained within the scale of about a kilometre of shore for the following 4-6 winters (on average). Their behaviour is partly determined by personality (a repeatable suite of predation-risk management characters resulting in shyer or bolder individuals regardless of circumstance). These consistent differences in individual behaviour may arise due to differences in genes as well as the environment experienced by the juveniles on arrival. In particular some areas have high levels of human disturbance and risk of successful attack by sparrowhawks, peregrines and merlins We propose to subject different individuals (matched according to general location) to different levels of risk and disturbance using individually targeted predator models and human disturbance applied to birds in the wild. We expect individuals to modify their distribution and risk-management behaviour according to their perception of predation risk and disturbance, and possibly their interaction. We also expect that experiences in an individual’s first winter to affect behaviour in subsequent winters and for older birds to be affected less by experimental treatments. Such experimental and also observational data will allow us to model usage of the shore in terms of how redshanks perceive and adjust to predation and disturbance risk, and so draw general conclusions of the possible short and long term effects of changes in predation and disturbance risk on animal distribution.
Deadline of application: 31st July 2012